The correction factors used in various standards to compare permeabilities, measured at different water temperatures, assume laminar flow through the geotextile. In such a situation the permeability is inversely proportional to the viscosity of the pore fluid. In reality the flow through a geotextile in a permeability test will have a laminar and a turbulent component. Therefore the temperature correction generally overestimates the real i:q.fluence of temperature. For a temperature change from 10 to 20 °C this overestimation can be as much as 30% for a highly permeable geotextile.
In the paper results of constant and falling head permeability tests are presented and compared with a theoretical description of the flow through the geotextile based on the Forchheimer relation.